1. Field of the Invention
The subject matter disclosed herein relates to a crankshaft assembly for a reciprocating internal combustion engine having a crankshaft position encoder which is mounted upon either a crankshaft output flange, or at the front of the crankshaft.
2. Discussion of Prior Art
Reciprocating internal combustion engines, particularly those employed in automotive vehicles, utilize a crankshaft having an output flange to which a flywheel or flex plate is fastened. The friction necessary to transmit torque between the engine's crankshaft and the flywheel is produced at least in part by clamping the flywheel to the output flange by means of threaded fasteners. Unfortunately, as engine output torques have increased, sometimes without a concomitant increase in the engine size, and often through the use power adders such as charge boosters, it has become increasingly difficult to transmit engine torques efficiently. Moreover, if a flywheel or flexplate begins to slip or shift upon a crankshaft, the resulting vibration, while annoying, is only a telltale of far greater problems, because rapid engine destruction may ensue. Although it is known to insert a friction-enhancing washer between a flywheel and a crankshaft output flange, this type of structure is problematic because the washer may be omitted inadvertently during the assembly process, with the result that the engine will likely fail due to slippage of the flywheel with respect to the crankshaft.
Most automotive engines utilize a crankshaft pulley, mounted at the end of the crankshaft opposite the flywheel or flexplate end. Depending upon the particular application, such crankshaft pulleys usually drive a number of accessories, such as a generator, water pump, air conditioning compressor, power steering pump, and others. This duty necessitates a high torque capacity joint between the crankshaft pulley and the crankshaft. While it is known to handle this torque requirement, at least in part, by a key inserted into a keyway defined by slots formed in the crank damper's hub and the crankshaft's pulley mounting surface. This arrangement is not entirely satisfactory, because the majority of the torque load is accommodated by the joint defined by the crankshaft damper bore and the crankshaft's snout. Unfortunately, higher torque operation requires a concomitant increase in the size of the joint, which is sometimes difficult to provide because there is insufficient space to package the joint.
It would be desirable to provide a crankshaft assembly with a friction-enhancing component interposed between the crankshaft and the flywheel or crankshaft pulley, wherein the introduced component is essential to the operation of the engine, to the extent that absence of the component will prevent the engine from operating. This will assure that the higher torque capacity provided by the friction enhancing component is always present during operation of the engine.